Identification of QTLs associated with resistance to Phomopsis pod blight (<i>Diaporthe toxica</i>) in <i>Lupinus albus</i>

Abstract

Phomopsis blight in Lupinus albus is caused by a fungal pathogen, Diaporthe toxica. It can invade all plant parts, leading to plant material becoming toxic to grazing animals, and potentially resulting in lupinosis. Identifying sources of resistance and breeding for resistance remains the best strategy for controlling Phomopsis and reducing lupinosis risks. However, loci associated with resistance to Phomopsis blight have not yet been identified. In this study, quantitative trait locus (QTL) analysis identified genomic regions associated with resistance to Phomopsis pod blight (PPB) using a linkage map of L. albus constructed previously from an F8 recombinant inbred line population derived from a cross between Kiev-Mutant (susceptible to PPB) and P27174 (resistant to PPB). Phenotyping was undertaken using a detached pod assay. In total, we identified eight QTLs for resistance to PPB on linkage group (LG) 3, LG6, LG10, LG12, LG17 and LG27 from different phenotyping environments. However, at least one QTL, QTL-5 on LG10 was consistently detected in both phenotyping environments and accounted for up to 28.2% of the total phenotypic variance. The results of this study showed that the QTL-2 on LG3 interacts epistatically with QTL-5 and QTL-6, which map on LG10 and LG12, respectively.

Validation of Diaporthe toxica resistance markers in European Lupinus angustifolius germplasm and identification of novel resistance donors for marker-assisted selection

“…Mandelup, and LanrBo in line Bo7212 (Fischer et al 2015;Yang et al 2004Yang et al , 2008. In contrast, D. toxica resistance in another Old World lupin crop, white lupin (Lupinus albus L.), is under polygenic control as revealed by quantitative trait loci mapping in recombinant inbred line population derived from a cross between the susceptible Ukrainian cultivar Kiev Mutant and the resistant Ethiopian primitive P27174 accession (Cowley et al 2014;Vipin et al 2013).…”

“…Incorporation of these alleles into breeding lines resulted in development of germplasm with a greatly reduced total alkaloid level, more than hundredfold lower than that of old cultivars (Kamel et al 2016). However, lupinosis still remains a serious threat for animals grazing on lupin stubble (Cowley et al 2014). The chemical factor causing lupinosis was revealed to be a phomopsin, a toxin produced by pathogenic fungi, Diaporthe toxica Will., Highet, Gams & Sivasith, anamorph Phomopsis sp.…”

Analyses Using SSR and DArT Molecular Markers Reveal that Ethiopian Accessions of White Lupin (&lt;i&gt;Lupinus albus&lt;/i&gt; L.) Represent a Unique Genepool

“…These genotypes were important because they included the parents of the mapping population used to produce the L. albus linkage maps [22] [25], to locate the loci for low seed-alkaloid content (pauper) [34], and to develop PCR markers for resistance to anthracnose [35] and phomopsis [31]. In addition, they included parents of other mapping populations made for use in research to identify markers for loci controlling Pleiochaeta Root Rot resistance, and low seed alkaloid content locus exiguus [6].…”

Localisation of Loci Involved in Resistance to &lt;i&gt;Diaporthe toxica&lt;/i&gt; and &lt;i&gt;Pleiochaeta setosa&lt;/i&gt; in White Lupin (&lt;i&gt;Lupinus albus&lt;/i&gt; L.)

“…Cowley et al [34] have reported that genetic inheritance underlying PB resistance is complex and at least eight genomic regions were associated with PB resistance evaluated on detached pods. In this study, we have identified at least one genomic region delimited with marker lPms-524453 which also showed association with resistance to pod PB on linkage group 12 [34]. This finding suggested that at least some common genomic region control resistance at the stem, and pod stages.…”

“…Data for each marker were normalized by its theoretical standard deviation under Hardy-Weinberg's equilibrium. The map locations of molecular markers that exhibited significant associations with PB and PRR resistance were identified in the existing linkage map of L. albus [25] [29] [34].…”